Cartridge-feeding mechanism for firearms



ay 30; 1950 D. M. WILLIAMS CARTRIDGE-mmm@ MECHANISM FOR FIREARMS 3 Sheets-Sheet 1 A mm om mmd/ No om' E n@ A E mw @u @l E @u h: E m ll. w l l v I l n l l I I LII M L. @n m; mnd:

Filed Oct. 4, 1947 D. M. wlLLlAMs 2509,32

3 Sheets-Sheet 2 /ff yew for CARTRIDGE-FEEDING MECHANISM FOR"'FIREARMS May 30, 1950 Filed oct. 4, 1947 May 30, 1950 D. M. wlLLlAMs CARTRIDGE-mmm@ MECHANISM FOR FIREARMS 3 Sheets-Sheet 3 Filed 001'.. 4, 1947 Patented May 30, 1950 UNITED CARTRIDGE-FEEDING MECHANISM FOR FIREARMS poration of Delaware Application October 4, 1947, Serial No. 777,943

7 Claims.

The present invention relates in general to firearms and more especially to improvements in the cartridge-feeding mechanism of a self-loading firearm of the type having a tubular magazine and cartridge-transfer means adapted to automatically transfer a cartridge from the tubular magazine to the chamber of the barrel.

An object of the invention is to provide an improved self-loading firearm which is safe and dependable in operation.

A further object of the invention is to provide a self-loading firearm of the class described with superior cartridge-feeding mechanism wherein cartridges are successively fed automatically from the magazine to the chamber of the barrel without the possibility of jamming or otherwise causing malfunctioning of the firearm.

A still further object of the invention is to provide a self-loading firearm of the class described with superior cartridge-feeding means wherein the breechblock and carrier coact to automatically deliver cartridges successively from the magazine of the firearm onto the carrier free from detrimental effects of recoil.

With the above and other objects in View, as will appear to those skilled in the art from the present disclosure, this invention includes all features in the said disclosure which are novel over the prior art and which are not claimed in any separate application.

In the accompanying drawings, in which certain modes of carrying out the present invention are shown for illustrative purposes:

Fig. 1 is a fragmentary side elevation partly in section of a self-loading firearm embodying the improved cartridge-feeding mechanism of this invention;

Fig. 2 is an enlarged fragmentary side elevation in section of the firearm of Fig. 1 showing a cartridge in the chamber of the barrel, the breech-block in breech-closing position, and a fresh cartridge extending out of the rear end of the magazine and held securely in this position by coaction of the carrier and the breechblock;

Fig. 3 is a view similar to Fig. 2 but with the cartridge partially extracted from the barrel by the partially-retracted breechblock, the latter and the carrier coacting to release the fresh cartridge onto the forward end of the carrier;

Fig. 4 is similar to Fig. 2 but with the breechblock at the end of its rearward excursion, the extracted cartridge having been ejected from the receiver and the fresh cartridge fully supported on the carrier;

Fig. 5 is similar to Fig. 2 but with the breechblock advanced part way forward in the receiver, the fresh cartridge being engaged by the forward end of the breechblock and partially advanced thereby into its chambered position;

Fig. 6 is an end view in section of the firearm on line S-B of Fig. 2 illustrating the relationship of the cartridge cutoff to the fresh cartridge which has partially emerged from the rear end of the magazine;

Fig. 7 is a perspective view ofthe cartridge cutoff;

Fig. 8 is a side elevation of the breechblock showing the improved cartridge-hold-down lug on the underside thereof;

Fig. 9 is a front end elevation of the breechblock;

Fig. 10 is a plan View of the bottom of the breechblock;

Fig. 11 is a plan view of the top of the cartridge-carrier; and

Fig. 12 is a side elevation of the cartridgecarrier.

The firearm herein chosen for illustrating the present invention is of the self-loading type in which the barrel is fixed to the receiver and a chamber-extension and breechblock move rearwardly as a unit on the discharge of the firearm, the chamber-extension being adapted to move forwardly thereafter relative to the breechblock and the latter subsequently moving lforwardly automatically to insert a fresh cartridge into the chamber of the barrel, as disclosed in my copending application Serial No. '733,617 led March 10, 1947, now Patent Number 2,506,982. In brief, the firearm includes a receiver I5, a trigger-plate I6 removably mounted in the underside of the receiver adjacent the rear end thereof, a barrel indicated by the reference character II secured at its rear end by a threaded connection or the like in an aperture I8 in the front wall I9 of the receiver, a tubular magazine indicated by the reference character 20 and secured at its rear end in an aperture 2| 'in the front Wall l 9 of the receiver and a buttstock indicated generally at 22 suitably secured to the rear wall 23 of the receiver.

Referring to Figs. 2 through 6, the receiver I5 has a top wall 24 and side walls 25 and 26 depending therefrom to form a substantially inverted U-shaped chamber for accommodating the breechblock and the nre-control mechanism. The latter is mounted in the trigger-plate I6 and embodies a pivoted hammer 2l and a trigger indicated generally at 28 for locking and releasing the hammer. Since the fire-control'mechanism is not essential to a full disclosure of the invention, further details of this mechanism are omitted. The breechblock or action of the firearm is indicated generally at 29 and is adapted to be supported in the receiver for both longitudinal and pivotal movement therein. To this end, suitable longitudinal guide-grooves 30 and 3l are provided in the inner walls of corresponding sides 25 and 26 of the receiver (see Fig. 6), each guidegroove extending throughout the length of the chamber. Referring particularly to Fig. 6, breechblock-guiding-and-supporting plates 32 and 33 respectively are adapted to be mounted in the corresponding longitudinal guide-grooves 3Q and 3| of the receiver and to be connected to the breech-bolt by means of longitudinal ribs 3d and 35 respectively, each being formed onthe inner wall of its respective guide-plate 'and arranged to engage in a longitudinal fantailed groove in the corresponding side of theY breechblock. Moreover, each side-plate is provided with a transverse aperture at its rear end, each of which is aligned axially withA the other so as'to receive a transverse pivot-pin 36. The latter is arranged to` extend through suitable rocker-shaped camslots 3T formed in the transversely-spaced parallel depending side walls of the breechblockto pivotally connect the latter'to the guide-plates 32 l' and 33. As indicated in Figs. 2 and: 6, the righthand side-plate 33 isalso provided with a laterally-extending finger-grip 38 which projects through the ejection-port 39 in the; receiver for manually operating Vthe breechblock;

The longitudinal and-pivotal movementsof the breechblock are controlled in part by means of an operating-link lid, the forward end of which is pivotally connected' to the breechblock bythe aforesaid transverse pivot-pin 35. The rear end A' of the operating-link'@ is pivotally connected to the forward end of an inertia-bar All which is supported for longitudinal sliding' movement in a sleeve l2 which, in turn, is secured to the rear l wall 23 of the receiver and' extends rearwardly through la longitudinal aperture of the buttstock Y 22. vAn action-springA 43 (see Fig. 1)"is mounted in an axially-aligned aperture of the buttstock rearwardly of the inertia-bar 4I andv is adapted to abut the rear end of the latter to resist rearward displacement thereof; and to return the latter, including the operating-link All and bree'chblock 29, to their respective forward positions'in the receiver following the' discharge of the firearm; A

As pointed out in the application referred to above, the breechblock 2'9 isadapted to be locked inbreech-closing position by engagement of the rear end of its locking-lug'tl with the forwardlyfacing shoulder of a longitudinal aperture 46 formed in the top wall of a chamber-extension member 41". The latter constitutes one element of a chamber-unit, indicated generally at d8, which is supported for limited longitudinal move'- ment inr the barrel and receiver of the firearm,

d the length of movement of the chamber-unit ben ing but a small fraction of the distance moved by the breechblock.

In addition to the usual axially-mounted spring-loaded firing-pin 49 and the extractor Eil, the breech-bolt is provided on its underside and at its forward end with an integral downwardlyprojecting rib or lug 5I which extends longitudinally of the breechblock and is substantially midway between the opposite sides thereof, as indicated clearly in Fig. 9. The lug 5! constitutes one element of the improved cartridge feeding-means of this invention and to this end, the bottom edge of the lug is formed with a forwardlyand-upwardly-sloping cam-surface 52, a rearwardly-and-upWardly-sloping cam-surface 53 and a substantially-horizontal flat or hold-down surface 54 intermediate the aforesaid forewardlyand-rearwardly-sloping cam-surfaces. The lug 5I of the breechblock is adapted to coact with a cartridge-carrier or elevator, as hereinafter described, to control delivery of fresh cartridges from the open rear end of the magazine onto the carrier. Y

The cartridge-carrier, indicated generally at 55, is similar to the` carrier shown and described in the above identified application, and comprises, briefly, an arm 5G having a cartridge-supporting spoon 5l at its forward end, the arm 5S being an integral rearwardly-projecting extension of the right-hand side of the spoon 5l, as indicated clearly in Fig. 11'. The carrier-arm 56 is pivotally supported in a vertical longitudinallyextending recess 58 in' the right-hand side wall of the trigger-plate by a transverse'pivot-pin 59 which extends through theA arm forwardly of its rearr end on which a carrier-actuating dog 5S ispivotall'y mounted. The latter is adapted normally t0 project upwardly and to be held in the path of the lowerright-hand edge of the breechblock by a spring 5| which is supported in the vertical recess 58 ofV the trigger-plate for longitudinal sliding movement therein, whereby rthe spring 6I functions both as the actuating-spring and as the carrier-spring. In its latter capacity, it is. adapted normally to resiliently hold the rear end' of the carrier upwardly,` whereby its forward end or spoon 5'! is held down in a position such that' the front edge 52' thereof is slightly below the open rear end of the tubular magazine 253. Moreover, inthe presentY embodiment, the front end of the spoon is provided with a' downwardlyand-forwardly-sloping beveled' surface or lip 53 which intersects the front. edge S2 thereof, while the length of the carrier is such that the front edge 62 of the spoon is located rearwardly of the open rear end of the magazine 28 a distance which may be less than but is preferably slightly greater thanY one-third the over-all length of the cartridge.

The operation 'of the carrier by the reciprocating breeohblock is fully described in the above identified application and hence it will suffice to say that when the breechblock is in its forward breech-closing position, as shown in Fig. 1, the force of the spring 6| resiliently holds thecarrier-spoon down in a position substantially opposite the open rear end of the magazine. Although not shown in the drawings, it'will be understood that any of the well known carrier-locking latches may be utilized to-positively lock the carrier in this position'. Now, as the breechblock moves rearwardly in the receiver, the right-hand bottom' edge of the breechblock is adapted initially to ride over the rearwardly-pivoting actuating-dog 5U, but on returning from its rearmost position in the receiver to engage with the actuating-dog as indicated in Fig. 4. If, at this time, the carrier is still locked by the aforementioned carrier-latch, then the breechblock will be held adjacent the rear end of the receiver in breechopen position. However, if the carrier-latch has been actuated by a cartridge delivered onto the carrier to release the latter, then the force of the action-return spring i3 will move the breechblock forwardly, mutual engagement of the latter and the actuating-dog acting to depress the rear end of the carrier and elevate its spoon 5l, as shown clearly in Fig. 5.

An additional element of the firearm is shown in Fig. E' and comprises a cartridge-cutoff consisting of a lever-member 64 pivoted on a transverse pivot-pin 55 intermediate its opposite ends in a suitable relief-recess on the inside wall of the left-hand side of the receiver. The forward end of the lever 5t is provided with an inwardlyand-downwardly-projecting toe 56 (see Fig. 6) shaped so as to be substantially concentric to the open rear end of the magazine. Formed on the upper edge of the forward end of the lever is an upwardly-projecting knee 31 which, as indicated in Fig. 2, is located directly beneath the bottom edge of the left-hand side-plate 33 of the breechbloclr., the knee being adapted to be engaged and held downwardly thereby when the breechblocl; is in its forward position so as to displace the toe t5 below the lower edge of the open rear end of the tubular magazine and permit egress of cartridge therefrom. The opposite or rear end of the lever-arm' ed is provided with an upwardly-projecting finger $8 which lies substantially in the vertical plane of the knee 61 of the lever-arm. The length of the cutoff-lever is such that the nger 58 will clear the rear end of the side-plate 33 and hence be free to swing upwardly thereby when its toe 65 is depressed. However, as the side-plate 33 and breechblock move rearwardly, the finger 5S is cammed downwardly by the side-plate 33 and so held during the major portion of the rearward and forward excursions thereof, whereby the toe 6 of the cutoff-lever is elevated to prevent egress of a fresh cartridge from the magazine during this interval.

Since the rearmost cartridge in the magazine is released by the cartridge-cutoff lever ed as the breechbloch moves into breech-closing position,

has been customary to provide cartridge stopmeaas to engage the rearmost cartridge in the magazine and temporarily prevent the cartridge from moving rearwardly onto the carrier, until such time as the breechblock begins its rearward movement in the receiver. Where a dependinglug at the front end of the breech-bolt has been used as a cartridge stop, the released cartridge has been held from rearward movement by abutment against the front edge of this dependinglug.

The present invention has its conception in the discovery that cartridge-stops of this latter type are the indirect, not the direct, cause of jams and other malfunctioning and that the released and rearmost cartridge of the magazine hereinafter' referred to for brevity as the fresh cartridge may be restrained from premature rearward movement onto the carrier by coaction of the breechblock-lug 5! and the forward end 52 of the carrier so as to preclude faulty operation of the firearm. In particular, it will be noted on reference to Fig. `2, that the head of the fresh cartridge is not in abutting engagement with the forward edge of the breechblocklug 5l, but is rearwardly thereof, and in direct engagement with the beveled lip 63 of the carrier, which as pointed outabove, permits substantially one-third the length of the fresh cartridge to extend out of the open rear end of the receiver.

Moreover, the fresh cartridge is securely held in contact with the beveled lip 63 of the carrier by a jamming action effected by the flat or holddown surface 5d of the lug 5l, which engages on the top of the rearwardly-projecting portion of the fresh cartridge and positively holds the latter and more especially its rim from riding upwardly and rearwardly on the beveled lip of the carrier. In this connection, it should be emphasized that the hold-down action of the breechblock-lug 5l is effectively maintained both while the breechblock is locked in breech-closing position and during an appreciable length of its rearward excursion following discharge of the firearm, which length corresponds to substantially one-third the length of the cartridge, as indicated clearly in Fig. 3. Thus, a relativelylong delay is introduced between the time the breechblock begins its rearward movement and the subsequent rearward movement of the fresh cartridge. For guns of this class having a fixed barrel and reciprocable breechblock, this delay is a major factor in insuring smooth and dependable operation.

An addition-al function of the breechblock-lug 5! is that of preventing the adverse effect of recoil on the fresh cartridge when the firearm is discharged. Normally, the effect of recoil is to slide the rearmost cartridge in the magazine forwardly and heretofore it has happened not infrequently that the rearmost or fresh cartridge about to be delivered onto the carrier has been moved forwardly sufficiently into the magazine so as to be caught by the cartridge cutoff, thereby interrupting the normal automatic action of the firearm.

The hold-down surface 54 of the improved breechblock-lug 5I of this invention provides both frictional and positive means to restrain the fresh cartridge from moving forwardly into the magazine on discharge of the firearm, the frictional restraint being effected by direct contact of the hold-down surface 54 with the upper` surface of the cartridge; and the positive restraint being effected by engagement of the rim of the cartridge-head with the rearwardly-andupwardly-sloping cam-surface 53 of the lug. Thus, assuming the recoil force was suiciently great to overcome the counteracting force of the magazine-spring S9 and the frictional restraint offered by engagement of the hold-down surface 54 of the lug 5I with the upper surface of the cartridge, then the latter would move forwardly until its rim struck against the rearwardly-andupwardly-sloping cam-surface 53; However, since the breechblock would be moving rearwardly, the rearwardly-moving cam-surface 53 of the lug 5| would positively counteract the forward movement of the cartridge and thus prevent the latter from ever` engaging the cartridge cutoff.

Referring particularly to Figs. 2 and 3, it will be seen that the foregoing conditions eXist when the breechblock is in breech-closing position and during the relatively-short interval following the discharge of the firearm in which the breechblock is unlocked Afrom the chamber-extension as oasaz 4l andv movesrearwardly a. distance corresponding substantially to the distance from the point offengagementof its lug :ilY with the top surface of the cartridge to the cartridge-rim at the rear end thereof.

As the breechblock continues its rearward movement, the breechblock-lug 5I is brought opposite the rear end of the shell, whereupon the rearwardly-sloping cam-surface 53 of the lug cams the rim of the cartridge-head downwardiy and slightly forwardly' on the beveled lip 63 of the'carrier, thus permitting the hold-down surface 54 of theA lug to pass over the rim of the cartridge. Thereafter, as the forwardly-andupwardly-inclined cam-surface 52 of the lug moves away from the cartridge-rim, the holddown. force directed' downwardly thereon by the bolt-lug, is gradually released, whereupon the cartridge, andv in particular its rim, is free to move upwardly and rearwardly on the beveled lip 63 of the carrier and thereafter rearwardly onto the carrier-spoon, both the upward and rearward movement of the cartridge on the carrier-lip E53 and its subsequent rearward movement onto the spoon being effected by the rearwardly-acting force of the magazine-spring 53S.

Thus, the fresh cartridge follows the breechblock rearwardly in the receiver but in all likelihood at a somewhat slower rate. Moreover, due

to the aforesaid delay in starting, any possibility' of the fresh cartridge running ahead of or so close behind the breechblock as to cause a jam byreleasingY the carrier before the fired cartridge hasbeen ejected, is avoided. When a fresh cartridge does arrive at its fully-supported position on the spoon of the carrier, the latter is adapted to be unlocked as, for example, by a cartridge-actuated latch (not shown), whereupon the force of the action-return spring #le urges the breechblock forwardly, thereby depressing the rear end of the carrier through the medium of its actuating-dog 6d and elevatingr itsforward end or spoon (see Fig. 5) to bring the fresh cartridge thereon up into a position in front of the face of the breech-bolt, whereby as the latter advances, it engages and chambers the fresh shell in the barrel of the firearm.

Just before the breechblock arrives in chamber-closing position, the knee el of the cartridgecutoff lever will be engaged by the bottom edge of the left-handfside-plate 33 and pivoted downwardly so as to withdraw the toe 66 from out of the bore of the tubular magazine, thereby releasing the next-succeeding rearmost cartridge therein. The latter is promptly thrust rearwardly from the open rear end of the magazine by the force of the magazine-spring 69 and brings up against the forwardly-and-upwardiy-sloping cam-surface 52 of the forwardly-moving breechblock-lug 5l which momentarily depresses the cartridge as it rides over the rim thereof. Immediately thereafter the hold-down surface 5d of the lug 5I will engage the top side of the cartridge forwardly of its rim, thereby pressing or jamming its rim down firmly in engagement with the beveled lip 63 of the carrier so as to preclude further rearward movement of the cartridge.

It will be appreciated from the foregoing description and the drawings, that coaction of the breech-bolt lug with the cartridge-carrier `provides cartridge-feeding means which affords a slight delay between the time the breech-bolt begins its rearward movement and the subsequent follow-up of the fresh cartridge. This delay, insures the successful extraction and ejection. of the fired cartridge from the receiver beforer the fresh cartridge can be elevated into position to interfere with or jam the fired cartridge. Although such circumstance is somewhat remote in firearms of the class having a recoiling barrel, the likelihood of jams occurring due to this cause in firearms having a stationary or fixed barrel is great. Moreover, by exerting a positive downwardly-directed force on the top side of the rearmost cartridge in the open rear end of the magazine so as to jam the rear end of the cartridge against the beveled front end of the carrier, the cartridge is positively held against premature rearward movement.

The invention may be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of the invention, and the present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes comingv within the meaning and equivalency range of the appended claims are intended to be embraced therein.

l claim:

l'. In a self-loading firearm, the combination including: a, receiver having a chamber; a barrel mounted on the forward end of said receiver; a tubular magazine supported beneath said barrel, said tubular magazine having an open rear end intersecting the forward end of said chamber and a magazine-spring arranged to project the rearmost cartridge in said magazine from the open rear end thereof into said chamber; a breechblock reciprocably mounted in said chamber; a cartridge-carrier pivotally mounted in said chamber; carrier-actuating means arranged to hold the forward end of said carrier normally opposite the open rear end of said magazine when said breechblock is in the forward end of said chamber; and means to control a cartridge projected onto said carrier from said magazine when said carrier is in its normal position, said controlmeans comprising a lip on the forward end of said carrier and an element mounted on said breechblock forwardly of said lip when the breechblock is in breech-closing position arranged to engage the top side of the cartridge substantially intermediate'the opposite ends thereof to hold said cartridge in engagement with the lip of said carrier on recoil of said firearm.

2. In a self-loading firearm, the combination including: a receiver having a chamber; a barrel mounted on the forward end of said receiver; a tubular' magazine supported beneath said barrel, said tubular magazine having an open rear end intersecting the forward end of said chamber and a magazine-spring arranged to project the rearmost cartridge in said magazine from the open rear end thereof into said chamber; a breech-l block reciprocably mounted in said chamber; a cartridge-carrier pivotally mounted in said chamber; carrier-actuating means arranged to hold the forward end of said carrier normally opposite the open rear end of said magazine when said breechblock is in the forward end of said chamber; and means to control a cartridge projected onto said carrier from said magazine when said carrier is in its normal position, said controlmeans comprising a beveled lip on the forward end of said carrier and a lug on the underside of said breechblock forwardly of said lip when the breechblock is in breech-closing position, said lug having a hold-down surface on its bottom edge arranged to engage the top side of the cartridge forwardly of its rim thereby to hold said cartridge from moving forwardly out of engagement with the beveled lip of said carrier on recoil of said rearm.

3. In a self-loading firearm, the combination including a receiver having a chamber; a barrel mounted on the forward end of said receiver; a tubular magazine supported beneath said barrel, said tubular magazine having an open rear end intersecting the forward end of said chamber and a magazine-spring arranged to project the rearmost cartridge in said magazine from the open rear end thereof into said chamber; a breechblock reciprocably mounted in said chamber; a cartridge-carrier pivotally mounted in said chamber; carrier-actuating means arranged to hold the forward end of said carrier normally opposite the open rear end of said magazine when said breechblock is in the forward end of said chamber; and means to control a cartridge projected onto said carrier from said magazine when said carrier is in its normal position, said controlmeans comprising a beveled lip on the forward end of said carrier and a lug on the underside of said breechblock forwardly of said lip when the breechblock is in breech-closing position, said lug having a hold-down surface on its bottom edge arranged to engage the top side of the cartridge forwardly of its rim thereby to hold said cartridge from moving forwardly out of engagement with the beveled lip of said carrier on recoil of said firearm, and an upwardly-and-rearwardly-sloping cam-surface on the bottom edge of said lug arranged to engage and depress the rim of said cartridge during the rearward movement of said breechblock relative to said held cartridge so as to permit said hold-down surface to ride thereover.

4. In a self-loading firearm, the combination including: a receiver having a chamber; a barrel mounted on the forward end of said receiver; a tubular magazine supported beneath said barrel, said tubular magazine having an open rear end intersecting the forward end of said chamber and a magazine-spring arranged to project the rearmost cartridge in said magazine from the Open rear end thereof into said chamber; a breechblock reciprocably mounted in said chamber; a cartridge-carrier pivotally mounted in said chamber; carrier-actuating means arranged to hold the forward end of said carrier normally opposite the open rear end of said magazine when said breechblock is in the forward end of said chamber; and means to control a cartridge projected onto said carrier from said magazine when said carrier is in its normal position, said control-means comprising a beveled lip on the forward end of said carrier and a lug on the underside of said breechblock forwardly of said lip when the breechblock is in breech-closing position, said lug having a hold-down surface on its bottom edge arranged to engage the top side of the cartridge forwardly of its rim thereby to hold said cartridge from moving forwardly out of engagement with the beveled lip of said carrier on recoil of said firearm, and an upwardlyand-forwardly-sloping cam-surface on the bottom edge of said lug arranged to release said held cartridge for rearward movement onto said carrier by said magazine-spring as said breechblock moves rearwardly relative thereto.

5. In a, self-loading firearm, the combination including: a receiver having a chamber; a barrel mounted on the forward end of said receiver; a tubular magazine supported beneath said barrel,

i said tubular magazine having an open rear end intersecting the forward end of said chamber and a magazine-spring arranged to project the rearmost cartridge in said magazine from the open rear end thereof into said chamber; =a breechblock reciprocably mounted in said chamber; a cartridge-carrier pivotally mounted in said chamber; carrier-actuating means arranged to hold the forward end of said carrier normally opposite the open rear end of said magazine when said breechblock is in the forward end of said chamber; and means to control a cartridge projected onto said carrier from said magazine when breechblock is in the forward end of said chamber, said control-means comprising a beveled lip on the forward end of said carrier and a lug on the underside of said breechblock forwardly of said lip when the breechblock is in breech-closing position, said lug having a substantially-iiat hold-down surface on its bottom edge arranged to engage the top side of the cartridge forwardly of its rim thereby to hold said cartridge from moving forwardly out of engagement with the beveled lip of said carrier, an upwardly-and-rearwardly-sloping cam-surface on the bottom edge of said lug rearwardly of said fiat hold-down surface arranged to engage and depress the rim of said held cartridge, so as to permit said flat hold-down surface to ride thereover during the rearward movement of said breechblock relative to said cartridge, and an upwardly-and-forwardly-sloping cam-surface on the bottom edge of said lug forwardly of said flat hold-down surface arranged to release said heid cartridge for rearward movement onto said carrier by said magazine-spring as said breechblock moves rearwardly relative thereto.

6. In a self-loading firearm, the combination including: a receiver having a chamber; a barrel mounted on the forward end of said receiver; a tubular magazine supported beneath said barrel, said tubular magazine having an open rear end intersecting the forward end of said chamber and a magazine-spring arranged to project the rearmost cartridge in said magazine from the open rear end thereof into said chamber; a breechblock reciprocably mounted in said chamber; and means to hold the cartridge projecting into said chamber from said magazine from moving forwardly into said magazine when said rearm is discharged, said cartridge-holding means comprising an element on said breechblock arranged to project downwardly from the underside thereof to frictionally engage the top side of said cartridge intermediate its oppoite ends when the breechblock is in breech-closing position.

7. In a self-loading firearm, the combination including: a receiver having a chamber; a barrel mounted on the forward end of said receiver; a tubular magazine supported beneath said barrel having an open rear end intersecting the forward end of said chamber and a magazine-spring arranged to project the rearmost cartridge in said magazine from the open rear end thereof into said chamber; a breechblock reciprocably mounted in said chamber; a cartridge-carrier pivotally mounted in said chamber; carrieractuating means arranged to hold the forward end of said carrier opposite the open rear end of said magazine; means to hold the cartridge projecting into said chamber from said magazine from moving forwardly into said magazine when said firearm is discharged, said cartridge-holding means comprising a lug projecting from the v.erica-:see

underside of said breechblock, said lug having a 1at lhold-down 4surface arranged to engage the Icartridge forwardly of the rim thereof When the `breechblock 4is in breech-closing position; and

a yrearwardly-andeupWardly-inclined cam-sur- ,5 Vface arranged to engage the rim of said cartridge to depress said rim below said hold-down surface during the rearward movement of said DAVID M. WILLIAMS.

12 REFERENCES GITE-D The following rfrences '-a're bf lrecord Ain the le of this lpatent:

UNITED kSTATES .PATENTS 'Number Name Date 730,870 Browningr June 16, 1903 803,389 Bernard Oct. 31, 1905 `961,412 Johnson 7 7- June 14, 1910 962,764 Johnson 1 June 28, 1910 2,090,340 Browning .f-Aug. 17, 1937 2,333,677 Roemer r1--..1 Nov. 9, 1943 

